Drop hammer board



M y 1939- T. ROBINSON I 2,153,334

DROP HAMMER BOARD Filed March 31, 1957 I a V Zia/6711 0711 1/" s 772077205205272507:

Patented May 16, 1939 UNITED STATES PATENT OFFICE 2,158,834 DROP HAMMER BOARD Thomas Robinson, Lakewood, Ohio, assignor to Raybestos-Manhattan, Inc., Passaic, N. J., a corporation of New Jersey This invention relates to improvements in boards for drop hammers and the like and refers specifically to a relatively rigid, tough board which is ideally adapted for the raising of the hammer head of a drop hammer, the board being characterized. in that it is possessed of desirable frictional characteristics and has no tendency whatsoever to split in use.

Drop hammers, particularly of large sizes, are

so designed that a board is used as the raising medium for the hammer head. The end of the board is secured to the hammer head and the board is confined between two opposed rolls which exert rolling pressure upon the board to move the same, thus raising the hammer head. Heretofore, such boards have been constructed of wood, preferably hard Wood such as maple. These boards have been constructed in solid form or have comprised laminated structures.

00 However, due to the fibrous character of the board and also the compression which the board is subjected to by the lifting rolls, said boards are very short lived and are extremely unreliable due primarily to the fact that the board being repeatedly compressed by the rolls splits and must be replaced. When such a board fails in practice the entire forge is not only rendered inoperative but the splitting of the board is frequently a source of danger to the operators.

One of the features of my invention resides in the provision of a board which can be used in conjunction with drop hammers, the board comprising essentially laminated fabric, preferably duck, which has been previously frictioned with rubber or other heat hardenable binder, the resulting board being cured to rock hardness. This type of board is extremely strong and dur able and displays no tendency whatsoever to split in service. In addition, due to its high rigidity the board does not appreciably flex when in upraised position, and consequently upon descent of the hammer, the board is not whipped. This whipping action inherent in boards heretofore used is particularly destructive to the boards.

Other objects and advantages of my invention will be apparent from the accompanying drawing and following detail description.

In the drawing,

Fig. 1 is a front elevational view of a board embodying the concepts of my invention.

Fig. 2 is a diagrammatic side elevational view of my board, the hammer mechanisms being illustrated in dotted line.

Fig. 3 is a transverse sectional View taken on line 3-3 of Fig. 1.

Fig. 4 is a view similar to Fig. 3 of a slightly modified form of my invention.

Fig. 5 is a fragmentary front elevational view of another modified form of my invention.

Fig. 6 is a transverse sectional View taken on line 6-6 of Fig. 5.

Referring in detail to the drawing, l indicates a drop hammer board constructed according to 10 the teachings of my invention. The board I is relatively elongated and is of appreciable width compared to its thickness.

The board I is built up of a series of layers of fabric 2, preferably duck, the layers of fabric 15 2 being previously frictioned or otherwise treated with rubber or other heat hardenable binder. Each of the layers 2 is preferably cut to the dimensions of. the board and a suitable number of such layers are plied together to produce a board of desired thickness. After plying the layers 2 the mass thus formed is subjected to heat and pressure, to densify and compress the board and also cure the binder.

In use, the board I is secured by means of suitable wedges 3 to a hammer head 4 of the drop H forge. The board I is disposed between a pair of oppositely positioned rolls 5 which bear uponthe opposite faces of the board. The drop hammer mechanism is such that when it is desired 30 to raise the hammer head 4 the rolls 5 on opposite sides of the board are brought closer to each other, thus pinching the board between them. The rolls are simultaneously rotated and by frictional engagement with the opposite surfaces of the board the board and hammer head are raised.

In Fig. 2 of the drawing the hammer head is shown in raised position. In this position, if the board used is not relatively rigid it will tend to deflect from the true vertical plane as indicated in dotted lines at 6 in Fig. 2. However, in view of the fact that the board I constructed in accordance with my invention is extremely hard and rigid, its degree of deflection when in upraised position is substantially negligible. When the hammer is to be dropped the pinching force exercised by the rolls 5 is relieved and the hammer head 4 drops by gravity. In View, however, of its enormous weight, the head 4, and conse-- 50 quently the board, descend at a terrific speed.

If the board while held in upraised position has deflected, a whipping action will take place when the hammer descends which is particularly destructive to the board. This undesirable action is substantially eliminated when my board is used.

Another disadvantageous feature of boards heretofore used, which also flows from the lack of rigidity of such boards, resides in a destructive buckling action which takes place at the moment of impact of the hammer. Obviously, when the hammer descends it travels at an extremely high velocity just before impact. The inertia of the board, being carried by the hammer head, frequently causes the board to buckle intermediate its length between the rollers and hammer head. This action, of course, is exceedingly destructive in boards heretofore used, but, due to the rigidity of my improved board such buckling action is reduced to a minimum.

Referring particularly to Fig. 4, a board I is shown in cross section. In this case the board comprises alternate layers of frictioned duck I or other treated fabric and interposed layers of rubber 8. The layer 1 similar to layer 2 may be frictioned with rubber or other suitable heat hardenable binder, and the layers 8 although preferably constructed of rubber, may also comprise other heat hardenable materials in layer form. Similar to the construction of the board I, the layers 1 and 8 may be plied to a suitable thickness and may be subsequently compressed and cured to densify the mass and cure the material incorporated in the layers 1 and the rubher or other heat hardenable binders comprising the layers 1. The structure I' has been found to be exceptionally rigid and its degree of deflection even in relatively great lengths is exceedingly small.

Referring particularly to Figs. 5 and 6 another modification of my invention is illustrated and comprises a board 9 which is constructed of plied fabric layers It), the layers being frictioned or otherwise treated with rubber or other heat hardenable binder. The mass of plied duck layers carries tranverse metallic rods 'II which are spaced throughout the length of the board 9, the rods II extending through the thickness of the r board. Adjacent each side edge of the board 9 ing the hammer contact the faces of the plied mass without bearing upon the edges of the bars I2.

As illustrated, the reinforced board 9 is constructed, insofar as the plied mass or body is concerned, similar to the board I. It is to be understood, of course, that the body of the board 9 may be constructed similar to the board I.

It is to be also understood that, other means of retention of the reinforcing bars I2 along the sides of the board in place of the rods I I is contemplated or, if desired, said reinforcing bars I2 may be embedded in the thickness of the board. Broadly, my invention contemplates a board constructed as has been hereinbefore described With or without reinforcing bars.

I claim as my invention:

1. A board for drop hammers comprising a plurality of superimposed plies of duck fabric treated with a heat hardenable binder, the plied fabric being subjected to heat and pressure to cure the binder to rock hardness and to form a dense, substantially rigid and inflexible unitary elongated structure.

'2. A board for drop hammers comprising a plurality of superimposed plies of duck fabric treated with rubber, the plied fabric being subjected to heat and pressure to cure the rubber to rock hardness and to form a dense, substantially rigid and inflexible unitary elongated structure.

3. A board for drop hammers comprising a plurality of superimposed plies of Woven fabric treated with a heat hardenable binder, having interposed plies constructed of heat hardenable sheets, the plied structure being subjected to heat and pressure to cure the heat hardenable materials to rock hardness and densify the board thus formed to provide a substantially rigid and inflexible unitary elongated body.

4. A board for drop hammers of greater length and width than thickness comprising a plurality of superimposed plies of woven fabric compressed and secured together by a cured heat hardenable binder to form a rigid inflexible and non-resilient elongated board, said board carrying spaced rods embedded in the thickness of the board and secured at their ends to reinforcing metallic members disposed adjacent opposite side edges of and co-extensive with the length of the board, the said metallic members being of a lesser thickness than the board and extending between and inwardly of the surfaces thereof.

THOMAS ROBINSON. 

